Leaving the Olney Theatre, my wife remarked: "I've been toldall my life that 'Juno and the Paycock' is a great play, but this is the first time I've believed it."

That could not be more accurate. James D. Waring's production wholly captures the play's shifting interior rhythms; and the cast, beaded by Pauline Flanagan, Robert Symonds and Jarlath Conroy, digs into Sean O'Casey's characters with rich eloquence.

This immensely satisfying production marks a new level for the string of Irish plays that annually hold the fifth slot in Olney's summer seasons. Director Waring, with his Irish blood and frequent directing assignments in Dublin, instinctively understands the cantankerous Irish blend of grim realities and spiritual longings.

Critic James Agate called the greatest play written in English since the days of Elizabeth I, and the satisfaction of Olney's production stems greatest playwritten in English since from the play itself - O'Casey's perception of the characters, his audacious blend of comedy and tragedy - as well as the dynamic skills of this particular cast.

In their Dublin tenement, Juno copes with son Johnny, twice injured "for Ireland"; daughter Mary, soon to be impregnated by a careless English lawyer; and husband "Captain Jack," shiftless cowardly and cruel to her, their children and his buddy "Joxer."

Bricklayer O'Casey, who took to playwriting because he disliked the plays he saw, draws characters of terrible truth but awesome humanity. This gallery of very real people, even minor parts, is as rich in frailties, prides and foolishness as it is in their author's acceptance of them. Waring lovingly gives them all their reins, encouraging moments which, less surely handled, could be scene-stealing.

Flanagan is a strikingly secure actress as Juno (her fourth time in the part) and breathes the woman's gallantry, talking or listening. When she comes to the final lines: "Sacred Heart O'Jesus, take away our hearts O'stone and give us hearts O' flesh," she displays superb power.

Symonds plays the Captain better than I have seen the part done, as does Conroy the role of Joxer, capturing the poetry of the words, the depths of characters. Their table scene, after Captain thinks he has inherited wealth, is a duet of fine actors at work, technical bravura which somehow never goes over the line.

Also fine are the scenes between Pat. Karpen's daughter Mary and Flanagan, mutually groping for O'Casey's slight current of union. Through Charles Lang's Johnny, Michael Haney's Jerry, James Handy's Bentham and Vivienne Shub's Mrs. Tancred, we glimpse the normous range of topics O'Casey poured into his play - nationalism, religion, Irish women, mysticism and literature. Toni Darnay, George Vogel, Blaise Corrigan, Ned Corrigan and John Phelan complete the company.

A final asset is Kaye Roscoe Byars' costuming detail: The shawl loaned to Mrs. Tancred by Maisie Madigan is exactly what that chatterbox would own and, so generously, lend.